1. Field of the Invention
This invention relates to a pharmaceutical composition for combatting viral infections and a method of using the composition thereof for treating viral infections. More particularly, this invention relates to a pharmaceutical composition for combatting viral infections comprising, as an active ingredient, an acylpeptide or its pharmaceutically acceptable salt, and to a method of use of the acylpeptide or its pharmaceutically acceptable salt for prophylaxis or therapentic treatment of infectious disease caused by viral in human beings or animals.
2. Description of the Prior Art
The acylpeptide to be used as the active ingredient in the pharmaceutical composition for combatting viral infections according to this invention is represented by the following formula (I): ##STR2## wherein R.sup.1 is lactoyl-alanyl, R.sup.2 is carboxymethylamino and R.sup.3 is carboxy; or R.sup.1 is heptanoyl, R.sup.2 is 1-carboxyethylamino and R.sup.3 is carboxy; or R.sup.1 is stearoyl, R.sup.2 is 1-carboxyethylamino and R.sup.3 is hydrogen; or R.sup.1 is octanoyl, R.sup.2 is 1-carboxyethylamino and R.sup.3 is hydrogen.
The acylpeptide of the above general formula (I) and pharmaceutically acceptable salts thereof are known to be compounds having immunopotentiating activity (cf. U.S. Pat. No. 4322341, for example).
The present inventors found that the acylpeptide (I) and pharmaceutically acceptable salts thereof have excellent preventive and therapeutic effects against various viral infections and, as a result of further research based on this new finding, have completed the present invention.